Dunno... SWAG is that the TR had some kind of failure. If you look at the video carefully, it almost looks like you can see the TR slow down as the ship swings around. Didn't look like LTE and winds seemed almost calm (based on fire and smoke pattern after crash).
Disclaimer, pure speculation; We can see that it is a flat calm day and the ship is moving, the stagnated air behind the ship would be "dirty" which may give the tailrotor difficulty "biting" to get the thrust needed, the pilot panicks and pulls pitch, making the situation worse.
But then again, it is more likely to have been a Tail rotor failure, who knows?
Helicopter crash
Groundhog day....
